1. Field of the Invention
This invention relates to medical methods and apparatus.
More particularly, this invention relates to methods and apparatus for vascular neuromuscular blockade.
In a further and more specific aspect, the instant invention relates to methods and apparatus for improving vascular patency.
2. Prior Art
The human cardiovascular system is a closed tubular system in which blood, propelled by a muscular heart, flows through vessels to and from all parts of the body. Two circuits, the pulmonary and the systemic, consist of arterial, capillary, and venous components.
These vessels are unfortunately prone to a variety of maladies, which can inhibit the flow of blood, ultimately causing substantial and serious bodily injury. For instance, the coronary arteries, which originate in the aorta and supply blood to the muscular tissue of the heart, are susceptible to atherosclerosis. Atherosclerosis is characterized by the narrowing of the artery from the deposition of atheromatous plaques containing cholesterol and lipids.
The prior art has provided certain procedures for correcting atherosclerosis. If an artery is incompletely obstructed, medication can be used for clearing the obstruction. Another commonly used technique is to surgically bypass the diseased portion if medication is not effective. This method is invasive, requires substantial recovery time and can be very expensive.
As a result, catheter guided vascular procedures have become more and more common for the treatment of atherosclerotic disease. Angioplasty is commonly employed for dilation of a partly obstructed vessel to restore blood flow. In angioplasty, the vessel is dilated by flattening the atheromatous material against and into the arterial wall. Although there are operative risks, such as emboli and tearing, the results seem to be acceptable and the technique may be repeated, if necessary. The inherent limitation of this corrective technique is that it is not a permanent corrective measure. Thus, in order for it to be effective, it must be periodically repeated, which is undesirable and can lead to considerable expense.
As a result of the inherent deficiencies described above in combination with angioplasty, which is normally used for repairing occlusive maladies or vascular constrictive maladies, a vascular insert that is introduced into the affected vessel proximate an affected area has been developed. The insert, commonly referred to as a stent, is typically a mesh of shape retaining material. The stent is introduced into a vessel for distending and buttressing the vessel outwardly thereby restoring the proper flow of blood through the vessel. The stent is normally permanently introduced into the affected vessel.
Stents are typically formed of a wire mesh, and therefore may only be used for repairing obstructive vesicular maladies, and are not useful for repairing fistula or aneurysms. A different vascular insert, commonly referred to as a graft, is employed to repair fistula or aneurysms. A graft is typically formed of dacron, Gortex and polytetrafluoroethylene materials and is inserted into a damaged vessel for use as a vascular conduit.
Catheter guided vascular procedures have become more and more common for the treatment of atherosclerotic disease. Catheter guided procedures for treating atherosclerosis include angioplasty and stenting. Percutaneous procedures are less invasive than conventional surgery and continue to increase in popularity for restoring blood flow and treating aneurysms. Unfortunately, restenosis or occlusion of a vessel is common after these procedures whether a stent is present or not. Also, smooth muscular contraction within the vessel carrying a graft can collapse the graft.
It would be highly advantageous, therefore, to remedy the foregoing and other deficiencies inherent in the prior art.
Accordingly, it is an object of the present invention to provide methods and apparatus for vascular neuromuscular blockage.
Another object of the present invention is to provide methods and apparatus to reduce restenosis of blood vessels.
And another object of the present invention is to provide methods and apparatus to prevent collapse of grafts in blood vessels.
Yet a further object of the present invention is to provide method and apparatus to eliminate vasospasm which occurs in the cerebral arteries following subarachnoid hemorrhage and in other blood vessels following other insults.
Briefly, to achieve the desired objects of the instant invention in accordance with a preferred embodiment thereof, provided is a method of vascular neuromuscular blockade including percutaneous delivery of a quantity of neurotransmitter inhibiting agent to an affected region of a vessel. The delivery of the agent is achieved by providing an endovascular device carrying the neurotransmitter inhibiting agent.
The endovascular device is shaped and sized for percutaneous insertion into a blood vessel and includes a collapsed configuration and an expanded configuration. A neurotransmitter inhibiting agent is carried by the device. Insertion and positioning of the device is accomplished with the device in the collapsed configuration. In the expanded configuration, the neurotransmitter inhibiting agent is driven into the walls of the blood vessel.